I would like to claim this please.
I've been working on a cave that should fit this exterior. What do you think about making it an abandoned mine? My idea is that the beginning of the mine is still mostly intact, but farther in the infrastructure gets more and more damaged. Possibly rock falls and the general instability of the area dissuaded further mining in the deeper areas, and the beginning area ran out of ore. Also, the bridge to the deeper areas was badly damaged by a rock fall, and it wasn't worth repairing, since it was liable to break again in the near future.